1. Technical Field
The present invention relates to an adjustable orthosis for stretching tissue in the human body. In particular, the present invention relates to an adjustable orthosis which can be used for stretching tissue such as ligaments, tendons or muscles around any joint during flexion or extension of the joint.
2. DESCRIPTION OF THE PRIOR ART
Best U.S. Pat. No. 4,612,919 shows an adjustable limb support for adjustably orienting the forearm and upper arm of a human patient in a variety of angular relationships to therapeutically treat the contracted muscles in the patient's arm.
Lonardo U.S. Pat. No. 4,848,326 shows a knee contracture correction device for straightening a contracted knee. The device includes a pair of rod assemblies each having opposite upper and lower ends and a pivotal Joint between the ends. The upper end of the rod assemblies is pivotally secured to the patient's thigh while the lower end is pivotally secured adjacent the patient's ankle. The pivotal joint of the rod assemblies is locked so as to define an obtuse angle slightly greater than the angle of contracture of the knee. Straps are then positioned immediately above and below the knee and fastened to the rod assemblies so as to stretch the knee ligaments and muscles. Periodically, the angle of the rod assemblies is increased until eventually the knee contracture is eliminated.
Hepburn U.S. Pat. No. 4,538,600 shows an adjustable splint assembly with a lower strut and an upper strut pivotably connected to the lower strut. An internal spring applies a force at the pivot point to align the upper and lower struts to straighten the limb to which the splint is attached. A similar device is also shown in Hepburn U.S. Pat. No. 4,508,111. Similar devices are in use and are sold under the trademark DYNASPLINT by Dynasplint Systems, Inc.
Rogers U.S. Pat. No. 4,844,454 shows a portable, manually operable knee exerciser having a handle grasped by the user to pivot the lower leg relative to the upper leg.
Brown U.S. Pat. No. 4,665,905 shows a dynamic elbow and knee extension device with a centrally positioned compression spring.
It is also known in the art to put a rigid element including a turnbuckle, on the inside angle of a joint, between two cuffs attached to limb segments and use the turnbuckle to vary the length of the rigid element to pull and push the limb segments relative to each other. It has been found that this device does not work very well in practice because it is cumbersome and difficult to obtain relatively full extension at the extreme of motion.